| Effect of the H1 blocker d-chlorpheniramine on cerebral blood flow in the conscious dog during normocapnic hypoxia. | |
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MedLine Citation:
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PMID: 9545617 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The mechanism causing cerebral vasodilatation during hypoxia remains unclear. A role for histamine is suspected because H2 receptor-blocking drugs blunt the hypoxia-induced increase in cerebral blood flow (CBF). Moreover, in vitro blockade of H1 receptors by chlorpheniramine decreases the vasodilatation of cerebral arteries that is induced by histamine. The present study tested the hypothesis that an H1 receptor blocker (d-chlorpheniramine) would have a similar effect in vivo during hypoxia. Isocapnic hypoxia (inspired oxygen fraction, FIO2 = 0.10; inspired carbon dioxide fraction, FICO2 = 0.035) was induced in 16 conscious dogs randomly divided into two groups: eight dogs received saline intravenously (controls) at time 0 (normoxia) and after 2 h and 4 h hypoxia, and the other eight dogs received d-chlorpheniramine intravenously (0.5 mg kg-1) to block the H1 receptors. Regional CBF was measured by the radioactive microspheres technique 15 min after each injection of d-chlorpheniramine or saline. In the control group, CBF increased during hypoxia in all regions of the brain. In the d-chlorpheniramine group, total CBF increased similarly after 2 h of hypoxia. After 4 h of hypoxia, the increase was limited, especially in the pons, cerebral peduncles, hippocampus, hypothalamus, thalamus, and occipital lobes (six out of 12 studied regions). It is concluded that the H1 blocker d-chlorpheniramine did not strongly inhibit the increase in CBF during hypoxia. After cumulative doses, however, as in the fourth hour of hypoxia, the increase in total CBF was limited. |
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Authors:
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G Audibert; J Siat; C Müller; D Hartemann; G Naja; C G Saunier; M C Laxenaire |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Clinical physiology (Oxford, England) Volume: 18 ISSN: 0144-5979 ISO Abbreviation: Clin Physiol Publication Date: 1998 Jan |
Date Detail:
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Created Date: 1998-06-08 Completed Date: 1998-06-08 Revised Date: 2007-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8309768 Medline TA: Clin Physiol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 27-33 Citation Subset: IM |
Affiliation:
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Departement d'Anesthésiologie, Hôpital Central, Nancy, France. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood Gas Analysis Cerebrovascular Circulation / drug effects* Chlorpheniramine / pharmacology* Dogs Female Hemodynamics / drug effects Histamine H1 Antagonists / pharmacology* Hypoxia, Brain / physiopathology* Male Microspheres |
| Chemical | |
Reg. No./Substance:
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0/Histamine H1 Antagonists; 132-22-9/Chlorpheniramine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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